Valve device for the automatic control of an air intake dependent on varying humidity

ABSTRACT

In a fresh air valve device having a throttle valve member (2) controlled by a humidity sensitive member (10), the control may be interrupted by means of a manual adjusting device (17) for compulsory opening and compulsory closing of the valve member.

This invention relates to a valve device for the automatic control of anair intake dependent on varying humidity with a view to maintain adesired degree of humidity in a room, comprising a throttle valvemounted in an air intake conduit and operatively connected with ahumidity sensitive member exposed to room air and consisting of asheetlike laminate which at varying humidity content tends to changecurvature.

Such a valve device is known from EP-A2-0068917, in particular FIG. 5thereof, in which the air intake conduit is controlled by a resilientvalve plate atempting to keep the conduit closed and which by means of apull cord is connected with a humidity sensitive laminate plate mountedin a coextensive conduit through which the humidified air is allowed toflow. By increasing curvature due to increasing content of humidity inthe room air the laminate plate overcomes the spring force of the valveplate, thereby compelling this plate to move in the opening direction.

The present invention particularly pays regard to the fact that it maybe desirable under certain circumstances to interrupt the automaticcontrol of the valve. For example, there may be some need for intake offresh air even at a comparatively low degree of humidity in the roomair, i.e. when the humidity sensitive member attempts to keep the valveclosed, or it may be desirable to keep the valve in its closing positionagainst outer wind pressures, even though the degree of humidity in theroom should cause an opening.

The purpose of the invention is fulfilled in that the humidity sensitivemember is associated with a manual adjusting device which in its extremepositions is adapted to cause a compulsory closing and compulsoryopening, respectively, of the valve by overcoming the tendency of thehumidity sensitive member to change its curvature and, in anintermediate position has no effect thereon.

Under normal conditions the manual adjusting device is in itsintermediate position so that the device in principle operates in thesame manner as the above mentioned prior device, i.e. providing for anenhanced and reduced fresh air intake at increasing and decreasingdegree of humidity in the room air, but an interruption of saidautomatic operation only requires a simple shifting of the adjustingdevice in the one or the other direction, in dependence on whether it isdesired to keep the valve open or closed.

The humidity sensitive member may in a known manner be a metal sheetlaminated with wood veneer and, as is also the case with the abovementioned prior design, at least at one end edge that is parallel to thefibre direction of the wood it may be so mounted in a housing throughwhich the humidified room air flows that it may freely, i.e. unimpededby the mounting means, assume a curvature corresponding to the actualdegree of humidity, and at a point spaced from the mounting it may beoperatively connected with the throttle valve. In this case it ispreferred, according to the invention, that the operative connectionincludes a rigid rod which at the humidity sensitive member isassociated with a pin projecting from an edge of said member andengaging a guideway provided in the manual adjusting device andallowing, in the center position of said device, an unimpeded movementof the pin between its positions corresponding to fully open and fullyclosed throttle valve and causing, by movement of the device away fromthe center position, a compulsory lateral displacement of the pin andthus also a compulsory opening and closing, respectively, of the valve.

This entails a relatively simple and safely operating structure that maybe of a very compact design so that the overall dimensions of the valvedevice may be kept appropriately small, particularly in case the manualadjusting device is a slide located in the housing and controlled to bedisplaced in a direction parallel to the edge adjacent the humiditysensitive member, and the guideways of which form an angle of about 45°with said direction.

Two embodiments of the valve device according to the invention areillustrated on the drawings, in which

FIG. 1 is a vertical sectional view of the device in a first embodimentwithout the said slide,

FIG. 2 is a horizontal partial view including the slide, and

FIG. 3 illustrates the valve device in the second embodiment, in aperspective view from the front and with the front wall of the housingomitted.

In FIG. 1, 1 designates a tube adapted to be mounted in a wall apertureand constituting the above mentioned fresh air conduit. It accommodatesan ordinary pivoted throttle valve member 2 which from the illustratedclosed position may be tilted to a horizontal, fully open position thatis merely indicated by a dotted line.

Through a mounting plate 3 with projecting bosses 4 the tube 1 isconnected with the rear wall 5 of a housing whose front wall and lateralwalls are provided with holes or slits 6 allowing the room air to flowinto the interior of the housing.

A square shaft 8 is mounted in a pair of flanges 7 at the top of thehousing and may be held in one or more positions by means of a lockingmechanism 9. The square shaft carries a thin, laminated wooden plate 10which tends to become curved, or increasingly curved, when subjected tomoistening, the plate being secured to the square shaft along an edgewhich is parallel to the general fibre direction of the wood. By apreferably releasable bracket 11 at its opposite edge the plate 10 isconnected with the valve member 2 through a rod 12 extending through aslit 13 in the rear wall 5 of the housing in order to cause the valve toopen when the plate 10 becomes more moist, thereby being further curvedso that its lower portion approaches the rear wall 5 of the housing.

An intermediate plate 14 having an opening 15 of appropriate size isfurther mounted on the bosses 4. In the space provided between the rearwall 5 of the housing and the intermediate plate an upwardly directedflow of room air may be effected which eliminates the cooling effect ofthe fresh air on the rear wall, thereby preventing condensate fromdepositing within the housing.

The bracket 11 is provided with a downwardly directed pin 16 engaging aslide 17 positioned at the bottom of the housing and not shown in FIG.1, but illustrated in a horizontal sectional view in FIG. 2. Said slideis displaceable parallel to the lower edge of the plate 10 and comprisesa pair of vertical oblique walls 18 whose angle in relation to thedirection of displacement is about 45° and which between themselves forma wide guideway 19 in which the pin 16 is received. A cord 20 serves todisplace the slide and is passed through a pair of slits 21 in thebottom of the housing. The slide may further, as illustrated, have aknob 22 projecting through a slit in the front wall of the housing, saidknob being alternatively used for manual displacement of the slide andbeing adapted to provide a visible indication of its position. Ifdesired, the device may further comprise an independent indicator forthe position of the valve, for instance a rotating indicator activatedmagnetically, in that the magnet may then appropriately be located atthe lower edge of the wooden plate 10.

In FIG. 2 the slide 17 is illustrated in the position corresponding toclosed valve. A movement of the pin 16 to the left is impeded by theupper one of said two oblique walls 18, and a moistening of the humiditysensitive plate 10 will therefore be without influence on the positionof the valve member 2. When the slide is displaced upwardly in FIG. 2,the pin 16 attains a successively increasing clearance of movement untilit gets clear of both oblique walls in the center position of the slide.By a continuous displacement of the slide in the same direction thelower oblique wall engages the pin 16 which will finally be held in aposition corresponding to fully open valve 2.

For the sake of completeness it should be mentioned that instead of thedisplaceable slide 17 a rotatable slide with a correspondingly modifiedguideway may be used.

In order that the humidity sensitive plate 10 may safely keep the valve2 closed at low air humidity and with the slide 17 in the centerposition, the plate should in this situation be pre-stressed to acertain degree. This may cause a retarding of the valve movement whenthe plate is being moistened and may also cause an overloading of theplate when the valve is forced open by means of the slide 17 which isaccompanied by a compulsory curvature of the plate.

These effects can be avoided by the embodiment of the valve deviceillustrated in FIG. 3 in which analogous elements have the samereference numerals as in FIGS. 1 and 2.

In FIG. 3 the humidity sensitive member 10 is almost rhombic andconsists of a laminate of a rear plate 10' insensitive to humidity andhaving an appropriate inherent rigidity, preferably a thin metallicplate, and a piece of wood veneer 10" that, however leaves the rearplate uncovered at the end edge portions parallel to the fibre directionof the wood. Said end edge portions constitute mounting flanges 23having a reduced width parallel to the fibre direction of the wood andeach engaging between a pair of needles 24 inserted through verticalholes in bearing bosses 26 on the rear wall 5 of the housing. Saidbosses may possibly comprise several holes for accommodating thehumidity sensitive member at an optional distance from the rear wallwith a view to adjusting the effective field of operation of said memberwhich may for instance be within the region from 45 to 65% relativehumidity corresponding to closed and fully open valve 2, respectively.

The explained accommodation entails that the member 10 when beingmoistened may freely curve or arch forwardly from the rear wall 5 andthus via the pin 16 may carry along the connecting rod not shown in FIG.3 (12, FIG. 1) for adjusting the valve position. Through a transverseslit in the upper one of two rails 25 mounted on the rear wall 5 andguiding the slide 17, the pin 16 is extended downwardly to the guideway19 of the slide, FIG. 2. In this embodiment the pin 16 is substantiallyparallel to the fibre direction of the veneer 10" and is secured to themember 10 intermediate its ends by means of a stirrup 11 mounted on thefront surface of said member and having backwardly directed earsprovided with holes adapted to receive the pin. By varying humidityconditions in the member 10 the pin 16 is forced to effect asubstantially translatorial movement in the form of a transversedisplacement towards and away from the rear wall 5.

In this case too, a compulsory closing or a compulsory opening willcause a certain deformation of the member 10, but such a deformation mayat any rate be substantially reduced to a torsion of the flanges 23 sothat no overloading of the humidity sensitive veneer coating 10" occurs.The reduced width of the flanges 23 in the fibre direction of the wood,as referred to above, for instance of about a fifth or a sixth of thewidth of the member at its middle portion may provide a torsionalresistance of appropriate size.

We claim:
 1. A valve device for the automatic control for the intakedependent on varying humidiity in order to maintain a desired degree ofhumidity in a room, comprising:a throttle valve mounted in an air intakeconduit, a humidity sensitive member exposed to the room air andcomprising a sheetlike laminate which at varying humidity content tendsto change its curvature, means for operatively connecting said throttlevalve with said humidity sensitive member, and a manual adjusting deviceassociated with said humidity sensitive member and movable between twoextreme positions in which said manual adjusting device keeps saidthrottle valve closed and open, respectively, by overcoming the tendencyof said humidity sensitive member to change its curvature, said manualadjusting device also having an intermediate position in which saidmanual adjusting device is operatively disconnected from said throttlevalve.
 2. A valve device for the automatic control of an air intakedependent on varying humidity in order to maintain a desired degree ofhumidity in a room, comprising:a throttle valve mounted in an air intakeconduit; a housing associated with said intake conduit and open to thehumidified air in the room, a humidity sensitive member in said housingtending to change its curvature in response to changes in humidity, saidhumidity sensitive member comprising a metal sheet laminated with woodveneer having a fibre direction, said humidity sensitive memberpresenting at least one edge which is parallel to the fibre direction ofthe wood; mounting means associated with said edge and allowing saidhumidity sensitive member to freely assume a curvature corresponding tothe actual degree of air humidity; and means for connecting saidhumidity sensitive member, at a point spaced from said mounting means,with said throttle valve, said connecting means including a rigid rodassociated with a pin projecting from an edge of said humidity sensitivemember and engaging a guideway provided in a manual adjusting devicewhich is movable to various positions, including an intermediateposition, in which said manual adjusting device allows an unimpededmovement of said pin between positions corresponding to fully open andfully closed positions of said throttle valve, said manual adjustingdevice also being movable to other positions in which said manualadjusting means causes compulsory lateral displacement of said pin andthus also a compulsory opening and closing, respectively, of saidthrottle valve.
 3. A valve device as claimed in claim 2, wherein saidhumidity sensitive member has an edge adjacent to said manual adjustingdevice, and said manual adjusting device is a slide located in saidhousing and guided for displacement in a direction parallel to saidadjacent edge of said humidity sensitive member, the guideway of saidslide forming an angle of about 45° with said direction.
 4. A valvedevice as claimed in claim 2, wherein said mounting means is provided atonly one edge of said humidity sensitive member, said humidity sensitivemember has an edge opposite said one edge, and said pin is secured toand protrudes from said opposite edge of said humidity sensitive member.5. A valve device as claimed in claim 2 wherein said humidity sensitivemember has two opposite end portions having edges parallel to the fibredirection of the wood, said mounting means comprises bearing means insaid housing for movably mounting said end portions to permit, inresponse to increasing humidity, arching of said humidity sensitivemember away from a plane defined by said bearing means, the pinassociated with the connecting rod being parallel to the fibre directionand being supported by said humidity sensitive member intermediate saidend portions.
 6. A valve device as claimed in claim 5, wherein the endportions of said humidity sensitive member comprise flanges of saidmetal sheet extending beyond said veneer, and said bearing meanscomprises bearings defining slits, each said end portion extending intoone of said slits.
 7. A valve device as claimed in claim 6, wherein thedimension of said flanges parallel to the fibre direction of the woodveneer is about one sixth of the corresponding dimension of saidhumidity sensitive member intermediate said flanges.
 8. A valve deviceas claimed in claim 5, wherein each of said slits is defined by a pairof parallel needles.
 9. A valve device as claimed in claim 8, whereinthe space between the needles is variable.